Very-low-calorie Diet Plans Can Be Safe With Supervision

When the Last Chance Diet Book hit the best-seller list in 1976, liquid- protein diets were the rage. By 1978, more than 100,000 people had sampled some sort of over-the-counter liquid-protein diet for rapid weight loss.

Nearly 60 fatalities among liquid-protein dieters were reported to the Centers for Disease Control. The causes of death never were fully explained, but a number were due to sudden deaths from cardiac arrhythmias (heartbeat irregularities).

Widespread media coverage and repeated Food and Drug Administration warnings about the dangers of unsupervised caloric restriction led to the rapid abandonment of that regimen as a self-help treatment. Meanwhile, the use and evaluation of very-low-calorie diets under strict medical conditions has continued. In contrast to many of the formulas produced for popular consumption in the heydey of the Last Chance Diet, the protein in these diets is of a high quality. Small amounts of lean meat, fish or poultry, or a powdered milk or egg-based formula may be used.

Small amounts of high-quality protein offer a distinct advantage over fasting as an approach to rapid weight loss. This prevents the loss of body protein, thereby protecting crucial organs from damage. The loss of protein from those formula diets of a decade ago was thought to contribute significantly to the cardiac disturbances.

Besides high-quality protein, very-low-calorie diets generally include supplements of vitamins and minerals. Among them are the so-called ''electroylytes'' essential for maintaining normal fluid balance.

These diets may or may not contain small amounts of carbohydrate. Some investigators feel that the elimination of carbohydrate and the resultant loss of appetite ease the dieting process. One study found that patients on a protein-sparing, modified fast reported significantly less hunger and preoccupation with eating than a group on a formula diet containing carbohydrate.

Weight loss is rapid at first, roughly between 4 and 11 pounds in the first week. Part of that loss is water. Thereafter, women average 2.2 to 4.4 pounds a week and men 3.3 to 5.6 pounds a week, practically all from fat.

These diets are not for everyone. Persons who have had a recent heart attack, or who have type 1 diabetes (formerly called juvenile-onset diabetes), serious liver or kidney disease, severe psychiatric disturbances or other major medical problems are not appropriate candidates. The diet never should be used during pregnancy.

Most doctors recommend such regimens only for adults who are moderately to severely obese (30 to 40 percent above ideal body weight), and then only for limited periods. They should be used under medical supervision. This means a professional medical evaluation before beginning the diet, including a detailed history, physical examination, and electrocardiogram, and continued surveillance during the diet. The regimen should include a support program designed to help the individual set realistic goals for coping with food- related problems and to provide information about nutrition, exercise and behavior change.

Even healthy subjects under supervision may have side effects. Possibilities include constipation, some generalized but transient loss of hair, cold intolerance and emotional disturbances. Despite these limitations, very-low-calorie diets can be effective at least in the short term. A review of eight major studies found that average weight loss over a 12-week period was 44 pounds compared to less than 15 pounds on more traditional diets.

By now, many people have been treated successfully without complications. The next question is whether weight loss can be maintained. About 50 percent of dieters may regain the weight they lost within 22 months. Moreover, the risk-to-benefit ratio involved in the yo-yo effect of weight reduction is unclear.

One thing that does seem to help keep weight off is a well-planned follow- up program. One group of investigators recently reported on their experiences with 668 individuals. They found that participation in a refeeding and maintenance program -- which included the gradual reintroduction of carbohydrate until a balanced diet was achieved, and weekly meetings with a counselor -- was an important predictor of long-term weight maintenance.

A very-low-calorie diet is a means to an end: rapid weight loss in a short period of time. But achieving that goal is only a first step. Only a follow-up program of diet, exercise and behavior modification can make that first step worth the effort.